While a link between swaddling and hip dysplasia (DDH) has been suggested for several decades, the role of swaddling in DDH is still unclear. Although it's unlikely that swaddling causes DDH, it's been proposed that tight swaddling around the hips, restricting hip flexion and abduction, may worsen the condition for those already at risk or malpositioned. The aim of this study was to assess whether a relationship exists between swaddling and severity of initial DDH diagnosis using a large dataset. This was a review of prospectively collected data from a single centre participating in a global prospective registry of patients diagnosed with DDH. We collected sex, age at diagnosis, clinical diagnosis, swaddling history (yes/no) and total swaddling duration (timing between the age at which the patient was first swaddled to the age at which swaddling ceased, in months) for all patients. All patients were then categorized according to the severity of their initial DDH diagnosis on clinical assessment: reduced and stable, reduced and unstable, dislocated and reducible, or dislocated and irreducible. For those with bilateral DDH, we categorized the diagnosis by the worst presenting hip. We then used ordinal regression models to investigate the relationship between DDH severity and swaddling history (yes/no), and DDH severity and total swaddling duration. A total of 534 patients were included in our analysis, 445 (83%) of whom were female. The average age at time of initial diagnosis was 6.2±12.1 months. Most patients presented with reduced and stable hips (381, 71%), while 80 (15%) were reduced and unstable, 50 (9%) were dislocated and reducible and 22 (4%) were dislocated and irreducible. Two hundred and thirty (43%) patients were reported as having been swaddled, with an average total duration of 1.8 months. There was no difference in proportion of female patients (p=0.329) or age at diagnosis (p=0.618) for those swaddled compared to those not. There was also no correlation found between swaddling and DDH severity, whether looking at swaddling history (yes/no, p=0.962) or total duration (p=0.953). Our study found no correlation between swaddling and initial DDH severity whether looking at swaddling history in general or total duration of swaddling in months. While it's been suggested that tight swaddling around the hips may contribute to worsening DDH severity, this has not been supported by our study. Future research should consider investigating whether prolonged swaddling may contribute to milder cases of acetabular dysplasia that develop later on in infancy.
Zomar et al. (Wed,) studied this question.